All categories

3 years ago

Identify the activity that belongs in the field of chemistry.

2 answers:

6 0

D, developing medicine, analyzing compounds and producing new product such as plastic both have to deal with chemistry. Since all need the knowledge of elements, compounds, etc.

Deffense [45]3 years ago

3 0

D. all of the above took the test

You might be interested in

A hydrogen fuel cell is an electrochemical reactor in which oxygen and hydrogen gas are reacted to produce energy. Rather than c

Contact [7]

Answer:

(d) Why is the fuel cell in Question (c) described as an alkaline fuel cell? (e) Another type of fuel cell uses methanol instead of hydrogen.

Explanation:

6 0

3 years ago

A population of rabbits triples every 2 months If there are 2 rabbits initially, how long will it take for the population to inc

Bezzdna [24]

Answer:

The rabbit population will reach 500 after 10 months.

Explanation:

According to the given data:

The initial number of rabbit's equals 2.

Number of rabbit's after 2 months =2x3= 6

Number of rabbit's after 4 months = 6x3=18

Number of rabbit's after 6 months = 18x3=54

Number of rabbit's after 8 months = 54x3=162

Thus we can see that the number of rabbit's form a Geometric series with common ratio =3 and initial term = 2

Now the general term of a geometric series with first term 'a' and common ratio 'r' is given by

$T_{n+1}=ar^{n}$

Thus we need to find when the term becomes 500 thus using the given data we have

$500=2\cdot 3^{n}\\\\3^{n}=250\\\\(n)log_3(3)=log_3(250)\\\\(n)=5.025\\\\$

Thus the fifth term (excluding the start term) will have a rabbit count of 500 now since each term has a time difference of 2 months thus sixth term will occur after $5\times 2=10months$

7 0

3 years ago

Typically, the hydrogen gas is bubbled through water for col- lection and becomes saturated with water vapor. Suppose 240. mL of

klio [65]

Answer:PH2=0.994atm, mass of zinc=0.606g

Explanation:

Equation for the reaction is written as;

Zn(s) + 2HCl(aq) - ZnCl2(aq) + H2(g)

V= 240ml = 0.240L

T= 30.8oC = 303.8K

Ptotal= 1.036atm

Pwater = 32mmHg at 30oC = 0.042atm

Therefore

PH2 = Ptotal - Pwater

= 1.036-0.042atm

=0.994atm

But PV= nRT

n = PV/RT

= 0.994x0.240/0.0821x303.8

= 0.24/24.94

=0.009324moles

For the grams of zinc

n=mass in grams/molar mass

Mass in grams = no of moles x molar mass

=0.009324x65 = 0.606g

3 0

3 years ago

List the following molecules in order from most reducedstate to most oxidizedstate: Formaldehyde (CH2O), Methane (CH4), Carbon D

AleksAgata [21]

Answer:

CH₄ < CH₃OH < CH₂O < HCOOH < CO₂

Explanation:

In order to know the oxidation number of C in these compounds, we will use the rule that states that the sum of the oxidation numbers of the atoms is equal to the charge of the compound, in these cases, zero because these are neutral molecules.

H is less electronegative than C, so it acts with the oxidation number +1.
O is more electronegative than C, so it acts with the oxidation number -1. When there is a double bond, it acts with the oxidation number -2.

Formaldehyde (CH₂O)

C + 2.H + O = 0

C + 2.(1) + (-2) = 0

C = 0

Methane (CH₄)

C + 4.H = 0

C + 4.(1) = 0

C = -4

Carbon Dioxide (CO₂)

C + 2.(O-double bond) = 0

C + 2.(-2) = 0

C = +4

Formic Acid (HCOOH)

In this case, we will just consider the H atom linked to the C atom.

C + 1.(H) + 1.(O-double bond) + 1.(O-single bond) = 0

C + 1.(1) + 1.(-2) + 1.(-1) = 0

C = 2

Methanol (CH₃OH)

In this case, we will just consider the H atoms linked to the C atom.

C + 3.(H) + 1.(O-single bond) = 0

C + 3.(1) + 1.(-1) = 0

C = -2

The order from most reduced to most oxidized is:

CH₄ < CH₃OH < CH₂O < HCOOH < CO₂

3 0

3 years ago

How would you prepare a 1 L solution of 3 M Mgo?

Alborosie

Answer: We need to 120 g of MgO in the beaker and add enough water to reach the 1 L mark.

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

$Molarity=\frac{n}{V_s}$

where,

n = moles of solute

$V_s$ = volume of solution in L

moles of $MgO$ = $\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{40g/mol}$

Now put all the given values in the formula of molality, we get

$3M=\frac{x}{40g/mol\times 1L}$

$x=120g$

Therefore, we need to 120 g of MgO in the beaker and add enough water to reach the 1 L mark.

3 0

3 years ago